


The Swap (Undertale AU: UnderSwap)

by Anonymous_Zyro



Series: Zak's Multiverse Collection [1]
Category: Undertale (Video Game)
Genre: F/M
Language: English
Status: Completed
Published: 2019-03-26
Updated: 2019-03-26
Packaged: 2019-12-18 09:17:19
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 15
Words: 4,884
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18246890
Author URL: https://archiveofourown.org/users/Anonymous_Zyro/pseuds/Anonymous_Zyro
Summary: Zak goes to on a mission to find Carnie, SaveHavenTale's Version of Chara, in UnderSwap. There he Meets US!Chara, who he saved from the fall by breaking her fall. They agree to travel together throughout the Underground, and eventually they fall in love, even though it's against his code.Undertale made by: Toby FoxUnderSwap made by: Undertale CommunitySaveHavenTale made by: Me





	1. PROLOG

I looked at the bright blue light as I stood in front of The Gateway. I looked up at the command room and at my creator, a boy no older than I was. He smiled at me, putting any doubt I had to rest and I ran up to the portal. I took a deep breath, and jumped.


	2. ONE

**Notes for the Chapter:**

> Points of View will Alternate between some Characters. It will usually alternate between Zak and Chara, but sometimes a different Point of View is introduced and then leaves after a few chapters.

I expected one thing when I fell, what I got was not it. I expected to fall and land on a hard rocky surface, feel the warmth of blood as I bled out at the bottom, not a boy to come out of a floating blue circle, whip chains out of his arms, wrap them around me, pull me towards him, wrap his arms around me, and land on a web of chains. I don’t know what happened after that, but one thing I remember, He was a damn hottie. I open my eyes slowly, and Instantly get a faceful of his face. “Gah!!” I launch up like an idiot and headbutt him hard without thinking. “Ow!! What the hell! Is that how people here thank a stranger for saving them?” He rubs his forehead, and I see how the chains appeared to come out of his arms. Actually, they were not in his arms, but wrapped around his arms. “S-Sorry!” I rub my head and wince at the pain when I touched it. The boy stood up and walked over to me, I must have blushed hard when he put his palm out and touched my forehead, because he smiled at me. “You’re pretty cute ya’know. Don’t want to let this bump stay there too long. Stay still so I can heal you faster.” He was right, my forehead didn’t hurt anymore. His palm was unnaturally soft and gentle, I wanted his hand to stay there. He removed his hand, and I mentally cried. He dusts himself off and looks around. “Welp. No way back up. Might as well find another way out.” He holds his hand down to me, and I grab it. “My Name is Zak, Nice to meet you!”, he smiles again, and I almost forget what my name was. “C-Chara! M-My Name’s Chara!”.


	3. TWO

I don’t know how a goat can walk on two legs, shoot fireballs, and talk, but somehow it can. “Hello Children! My name is Asgore, Caretaker of the Ruins. You look a little hungry, let me guide you through the ruins to my home, I make a great cinnamon-butterscotch pie if you would like to have a piece.” Chara latched onto my hand, and Asgore must have noticed. “Oh, you must be siblings. How nice of you to take care of each other, even if you both fell down.” Me and Chara both blushed, Chara seemed more embarrassed than me, because she let go of my hand immediately and crossed her arms. I smile and look at her, “It’s ok sis, you can hold my hand.” She looked back at me, and understood my message: ‘Play along, we might last longer.’ She took my hand again and walked next to me as we walked behind Asgore, following him through puzzles and stopping only once to ‘talk’ with a dummy. Me and Chara looked up at the massive purple stone structure that Asgore resided in. “Holy Jesus.” “This is my house,” Asgore stated as we passed through the doorway, “Feel free to look around and make yourselves comfortable.” Asgore walked into a room adjacent to the one we stood in, and an awkward moment of silence fell into the room. I look at Chara, who was blushing, “Hey Chara?” Chara jumped and yelped, like her sides were just squeezed. “Y-Yeah Z-Zak?” “Why did you jump?”


	4. THREE

I look away from Zak, he knew why I jumped, but he wanted to know more. He was hot, but curious as well...He’s the one who saved me, so I owe him an explanation. “I was bullied on the surface. Everyone, including my family hated me. They told me I was a mistake, a waste, that I should just kill myself. So I climbed up the mountain and decided to jump, but you saved me...You saved a total stranger when it could have costed you your life...Why did you save me when you didn’t even know me?” I look up at Zak, I was crying and I hated myself for it. He wrapped his arms around me and hugged me. I hugged him back, and cried into his shoulder, the inside of his hoodie was soft and warm, I didn’t want to let go. “Well. I guess it was just reflex. I was taught never to let someone get hurt, even if it puts you at risk.” I hug Zak tighter, the warmth of his body piercing through the coldness of mine. “Don’t let me go Zak. I don’t want you to leave me like everyone else did.” I cry into his shoulder again, but instead of responding in words, he lifts my chin up with his finger and puts his lips to mine. My first kiss, and it was with Zak.


	5. FOUR

My first kiss, and it was with Chara. Her lip quivered and her tears soaked into our lips. I pull away and look at Chara. “Z-Zak…” Her eyes glistened in the light of the lamp nearby, making my heart flutter a little. I put my hand to her cheek, and she tilted her head in response. I used my thumb to wipe away her tears, and she put her hands on top of mine. She never had anybody care for her, she must be overwhelmed with emotions she never felt before. I caught an image of a girl, she looked like Chara, but had a purple and pink shirt instead of a green and yellow shirt, but when I looked over, she was gone. “Z-Zak? Is something wrong?” I look closely at the spot I saw the image, making sure nothing was there. “I-I thought I saw something…It was nothing.” We jumped as Asgore knocked on the frame of the room behind us. “The pie is ready! Come sit and have a slice.”  
Me and Chara sit down at a huge table in Asgore’s Dining Room. There were two plates, each one with a slice of delicious looking cinnamon-butterscotch pie in the middle of the plate. Me and Chara pick up the forks that were next to the plates and take a bite. I look at Chara, and she looks at me. “Are you tasting the same thing I am?” “Are you?” We look at Asgore, who looks utterly confused. We stare at him, “What?” He tilts his head, even more confused. We hold up empty plates, “More please?” We both give him silly, child-like grins, and he grins back.  
After having another slice of pie, Asgore leads us down a hallway and opens up a spare bedroom where there is two beds and some nightclothes. “You should get some rest children. I’m sure you eager to leave, but you need to rest after having taken that big of a fall.” I look at Chara, and she looks back, both of us red in the face. “Well, I’m in the room nextdoor if you need anything. Sleep well children!” Asgore walks down the hallway, and I close the door. “U-uhhm...Wh-what side d-d-do you want?” I stutter as I try to recollect myself. I feel Chara’s arms wrap around my body and her hands come to rest on my chest. “I-I want t-to s-sleep with you i-if that’s a-alright?” I go red and nod. “Y-You should pr-probably change...I-I need to get a drink…” I step outside of the room and walk to the kitchen. Something tells me that my Creator knew this would happen, but I gulp down the thought with the glass of water. This was going to be an interesting journey.


	6. FIVE

After that night with Zak, I never want to leave him. We didn’t do anything but go to sleep in the same bed, but I still felt like I was going to burst. He never changed into the nightclothes Asgore gave us, which confused me a little bit. I assume it was because of the chains, which, I don’t know how I did not notice this sooner, had heavy metal balls at the ends. He told me they were called “Meteor Hammers”, and that the chain generates from inside his arm by using soul magic. He told me that there are usually seven coloured souls, but new ones will pop up very scarcely.  
Asgore led us down to the end of the Ruins, which was underneath his house. Zak and I thanked Asgore for letting us stay. “We’ll get you and everyone else down here in the Underground out of here, right Chara?” I nod. We give Asgore a hug goodbye, saying we will be back when we have broken the barrier. Zak and I push open the two massive doors that lead out of the Ruins, and step into a snowy forest.  
We walked for some time before stopping at a wooden bridge with metal bars, big enough for anything to pass through, crossing over the bridge. We looked at each other in confusion, not really understanding what the metal bars were for. “Hey, don’t you know how to greet a new pal?” We froze, but Zak must have protective instincts for me, as he whipped one of his meteors behind us and pushed me behind him. A bone rose from the ground, stopping at Zak’s neck. I peeked over Zak’s shoulder, and saw a tall skeleton in a orange hoodie, brown shorts, and orange sneakers. The skeleton’s left eye glowed orange and emitted a orange flame, and Zak’s left eye glowed grey and emitted a gray flame. Zak’s meteor was wrapped around the skeleton’s soul, but the bone would pierce his neck if he tried. A stalemate.


	7. SIX

**Notes for the Chapter:**

> The POV of this Chapter is from Swap!Papyrus' View. Enjoy!

I was one for laziness, my brother always reminded me of that. “PAPYRUS! LETS GO! IT’S TIME FOR OUR PATROL!!” Never expected to find or encounter one let alone two, one with insane magic. His chains wrapped around my soul, no biggie. My soul has been touched before, but these chains were different. I started to feel Fear run up my spine the longer we continued this stalemate. “you got nice reflexes kid.” “Thanks, I’ve been told.” The chain kid’s left eye glowed grey, and emitted a grey flame, a lot like my left eye. “we let go on three, ok kid?” “Sure.” After counting to three, my soul was released, and my bone attack backed away. I noticed the other human stood behind the chain kid, like the chain kid was protecting her. Must be brother and sister. I walk up to the chain kid and hold out my hand, no prank this time. “name’s papyrus” the chain kid took my hand, and shook it. “Zak, She’s Chara.” “your sister?” Zak seems to blush, Chara as well. “N-No...W-Were not related…” I shrug, not my business then. “you came out of the ruins then?” “Y-Yeah...Zak saved me from the fall with h-his chains…” Chara responded this time, her arms wrapped around him, but still hiding behind him. I look at Zak’s arms, and there were the chains. “where ya kid’s heading?” “Barrier. Going to break it down.” That woke me up real good, haven’t heard that before. “you’ll need to go to the queen’s castle, i’m sure she’ll let you try.” Chara peeks over Zak’s shoulder, she seemed to be afraid of me. “don’t worry kid, i won’t hurt ya.” I squat down and pull out my cigarette. I’m abnormally tall for a skeleton, so squatting is necessary for me to be eye level.  
I lead Zak and Chara into Snowdin, the town me and my brother lived in. told them they could stay with us as long as they needed. “PAPYRUS!!!” I jump from not expecting him so soon. “PAPYRUS! YOU WERE SUPPOSED TO BE ON PATROL! AND WHAT ARE THOSE THINGS FOLLOWING YOU?” I start to stutter as I try to gather my words. Thankfully Zak takes lead. “We’re Humans. Papyrus managed to catch us at the metal bars. Are you his higher up?” Zak looks up at me and winks, telling me to play along. Chara still hid behind Zak, peeking out at my brother over his shoulder. “yeah bro. just bringing them to you so alphys can finally get you that royal guard position. sans, just please use their names, Zak is this one, the other one behind him is Chara.” I point my finger above their heads, and Sans’ eyes light up. “NICE TO MEET YOU HUMANS! I AM THE MAGNIFICENT SANS! I’M SURE ALPHYS WILL BE GLAD TO SEE YOU WHEN I TELL HER THAT WE CAUGHT TWO HUMANS!!! NOT JUST ONE, BUT TWO!!!”. Oh boy...this is not gonna go well…


	8. SEVEN

**Notes for the Chapter:**

> Back to Zak's POV. (Rhyme ik)

Some time has passed since we met Sans and Papyrus, and I can already say that Chara likes it in Snowdin. Chara and I still sleep together, sharing the couch in the brother’s house. Papyrus is somewhat lazy when it comes to working, but cares and looks up to Sans. Who is energetic and always ready to work, often pressing Papyrus to do the same. Sans loves tacos, and seems to only know how to make tacos...Papyrus apparently drinks honey or maple syrup straight from the bottle, sometimes swapping it out with alcohol or Muffet’s Spider Whiskey. I wandered into Waterfall looking for Papyrus as a favor to Sans, and happen to come across a patch of large blue Echo Flowers. I tell myself to bring Chara here when I return to Snowdin. I kneel down to look at one, and a axe lands in front of me. “Well, Well, Well...A Human...What a nice surprise” I sigh and stand up, “Hello Alphys, Head of the Royal Guard. Sans told me a lot about you…” My Meteors fall into my hand, the cold magic steel slowly warming up in my hand. I whip one at the axe, and toss it back to Alphys, who was kind of surprised. “I’m in a hurry, let’s make this quick” I turn, my eye glowing grey. “Let's have a Chaotic Time!”


	9. EIGHT

**Notes for the Chapter:**

> Alphys' POV this Chapter

This human is different, their soul is nothing I have ever seen before. It’s a broken grey soul, but chains hold it together, and I can feel fear crawl up my back. I grip my axe and charge at the human, but what happens next is a blur: a blur of grey, pain in the side of my head, and then waking up in Undyne’s lab. Undyne tells me that the human I fought took me out with a single blow, but didn’t kill me, instead just delivered my unconscious body to the front door of the lab. Undyne tells me that my HP never went down with his attack, meaning he used a non-lethal self-defense move. This human would be too dangerous to try to capture, but he doesn’t seem to want to kill monsters, Nor has he killed any monsters since he and the other human came out of the ruins. He seems to only become lethally hostile when the other human is attacked, some sort of protective attachment to the other human. I curse under my breath and sigh, nothing we can do to stop them. I ask Undyne if she had any manga, I was kinda bored.


	10. NINE

**Notes for the Chapter:**

> Back to Chara's POV

“You wanna see something I found in Waterfall Chara?” I had no idea what he meant when he said that, but I caught on pretty quick: this was a date. I gasped at all the beautiful blue Echo Flowers that made up this little meadow. Zak laughs as he and I say funny puns into the Echo Flowers and listen to them repeat the pun in their echo. He makes me a flower crown out of some of the Echo Flowers and showed me the glistening lights above us, telling me about them and how he came here through the portal. “You were sent here...to ask the monsters for help?” “Yep. My Creator needs people to help him with something, I don’t know what it is, but my older brothers help him out all the time. He’s like my father or something like that…” I look at him as he stares at the lights, smiling his goofy grin I totally don’t want to kiss. He looks at me and motions for me to lay next to him, and I do. He wraps his arm around my shoulders and holds me. “Zak?” “Yeah?” “Close your eyes” “Okay?” He closes his eyes, and I blush. I climb on top of him and lay there, kissing him deeply. He blushes and kisses back for what feels like eternity. I don’t want this moment to end...I just want him, and nothing more…


	11. TEN

NST Resort Hotel, run by Napstaton, built by Napstaton, everything about this place is Napstaton. Me and Chara were told by Papyrus that Hotlands was the last area before the Queen’s area, and it is home of Dr. Undyne’s Lab and this place. Papyrus said it wasn’t that good of a place to eat or drink, but it’s a needed place to go before meeting Queen Toriel. We step into the Hotel and immediately get a to-close-for-comfort look of Napstaton, who was grinning like a kid seeing his favorite Saturday morning cartoon during a marathon. “Well well well, two cute little humans walked into my Hotel! What a blessing!” Me and Chara look at each other, confused as hell as what he just said. “Welcome! Please, make yourself comfortable! The show will begin momentarily!” Chara looks up at me, looking for an answer that I did not have, so I shrug in response. We look around the lobby, looking at pictures and listening to the echoes of a few potted Echo Flowers. Napstaton returned after a while, Chara fell asleep on my lap because she got bored. “Ok, we are ready to have you join us!” I look at Napstaton, I woke Chara up a few seconds before, so she was rubbing the tiredness out of her eyes, “What kind of show Napstaton?” Chara asks for me to carry her on my back, she was still very tired. I pick her up and follow Napstaton, who leads us out to a massive stage. This is gonna suck.


	12. ELEVEN

Napstaton challenged me to a duel, the one who could get the most ratings wins. I groan and roll my eyes. “Alphys already lost to me...Why would I duel against you if I know I’ll win?” Napstaton gasped, but something distracted both of us with a ding, it was a rating meter. Napstaton looked back in shock, and I had to win with the lead I stole, I had cat ears and a tail now, acting cute on purpose. Napstaton jumped when he turned back around and saw me, and he knew what I was doing, he couldn’t win with the edge that I had, and he knew it. “I-I lost already?!” I stopped and patted Napstaton on the shoulder. “Hey, here’s a tip, from one performer to another, I can tell you don’t enjoy what your doing here” I wave my hand at the stage, meaning his show type, “You would rather be making music, comedy shows, and you like fashion, do a fashion show every once in a while, You will be happier. And so will your fans and your ratings will be higher…” I pick up Chara again, who I had to set down in order to act cute. “Take my word for it Napstaton, it’s worth it”. Napstaton looked at me with a kind of amazement, and I smiled back at him, giving him a thumbs up. It’s time to go see Queen Toriel.


	13. TWELVE

Zak seemed comfortable with the heat, I wasn’t. “Are you getting to hot? I can see if one of my brothers can bring us some new clothes and some supplies...I’m kinda hungry and Pap’s stand is kinda far from here…” I look at Zak, kinda confused. “I guess, but how are they going to get here?” He pulls out a phone from his back pocket and presses a button, it rings and clicks, and a voice speaks from the phone. “Ello?” “Heya Fox! Can you bring me a light green and yellow female shirt, some provisions, and some healing items? I need them.” “Yeah I can do that, but I’m questioning why you need a girl’s shirt, do you have a girl with you?” I blush hard and cover my face. “Yeah, we’re in Hotlands and she’s getting to hot with the clothes she has on right now.” “Ok then, I’ll send Anima to you, I’m on a supply run myself.” “Thanks Fox!” “No Problem Zakary!” “Don’t call me that Foxorian! I can do that to the same thing to you!” I hear laughter from the phone and see Zak blushing, his full name was Zakary… “OK, I had my laugh, Anima’s on his way!”   
The phone bleeps as the call ends, and a whirr scares me from behind. “Zak, you called for supplies?” I turn around, and almost fall back from looking up, Zak was taller than me by a foot, this guy was 4-5 feet taller than Zak. “Hey Anima! Thanks for the supplies.” Anima had to kneel to give the basket to Zak, who pointed out a piece of metal on Anima’s arm. Anima said he got into a scrap and needed repairs, which made me realize that Anima was a robot. Zak thanked Anima and he disappeared through a blue portal, the same one Zak came out of, as Zak later told me more about the portal. Zak looked through the basket and pulled out a shoulder-less green and yellow shirt. “This must be for you Chara, See if it fits!” He tosses me the shirt and I look at it. Zak seemed to be busy with the basket, so I change into the shirt right there. It fits nicely against my breasts and the sleeves are loose and baggy at the bottom. “It fits Zak! How do I look?” Zak looks over to me and blushes, “You look great Chara!” I smile and sit down next to him. He pulls out two sandwiches and hands me one. We eat the sandwiches and talk about where we were from, and after we finished we took off again through Hotlands. Anima said that Undyne’s lab was not far off, and said to visit her to collect a upgrade for the phone Asgore gave me. It sounded like a good idea, and my phone was a bit busted.  
We reached the lab fairly quickly, barely a five minute walk. Zak knocked on the door, “Hello? Undyne?” No response. “I guess Undyne might be out. Should we come back later?” Zak shook his head. “No, Anima said Undyne barely leaves the lab unless she’s visiting the Queen, Sans and Papyrus, The Flowey Village, the cameras she placed around The Underground for maintenance, or Alphys. She should be here”. We look at each other for a few seconds, and the lab door opens with a hydraulic hiss and steam. Zak looks back at me with a “I told you” look, clearly being a tease. I roll my eyes and we walk in.


	14. THIRTEEN

Undyne’s lab was kinda messy, but that was kinda expected for the Head Royal Scientist. I look over at Zak as he steps forward to the computer. There were cameras showing multiple areas in The Underground. He watched one for a few seconds then moved on to the next one, almost like he was looking for something. “H-H-HEY!” I look behind me and stare at Undyne, who was holding a taser looking thing. I raised my hands and watched Undyne walk up. I turn my head to the side as she strode up to me, then walked past me. I look over an watch as Undyne walks up to Zak and asks him what he was doing. “Looking for something...sorry for not asking first.” he didn’t seem worried about the taser Undyne was holding. “W-What are you looking for human?” “That’s on a need-to-know basis, I can’t tell you without authorization.” Undyne puts the taser to the back of his head, he doesn’t seem to react. “T-T-Tell me!” “Give her phone a upgrade, then I’ll tell you…” Zak points to me, and Undyne follows his finger. She walks up to me with her hand out, asking to see the phone. I hand Undyne the phone and she takes it to a desk nearby. “T-The casing is broken a-a little, h-how did that h-happen?” I blush furiously and look away. Undyne must have seen me blush, “O-Oh! M-My b-bad!” I look back to the desk as Undyne works. “H-Hey human, m-mind d-doing me a favor?” I nod in response, “Yeah, what do you need?” Undyne looks over to Zak, not moving her head. “He’s making himself look weaker than he really is. See if you can get a good look at his soul for me? I want to know what it looks like.” I blush hard, but Zak responded for me. “I got nothing to hide, you want to look at my soul, go right ahead…” We look up at him and see his soul floating in his hand, and I nearly cry. It was a grey soul, broken partly down the middle and held together by grey chains. Magic was dripping from the chains, but not into his hands or the floor. “My soul is the Broken Soul of Fear, it’s also called the Soul of Broken Fear, the Soul of Chains, and the Soul of No Fear” Undyne runs up to Zak and *Check’s him, he has 0/0 HP, his attack and defence are glitchy and unreadable. “My creator made me like this on purpose, 0 HP so I couldn’t end up like Anti and Withered. Withered and Anti were the oldest of my siblings, Withered died in The First Corruption War and Anti went missing, Anti Came back in The Second Corruption War, trying to corrupt everyone he blamed for Withered’s death. I’m gathering allies to help fight against Negative and Infection, my Creator can’t fight this alone with his own power, and created a few new creations, me being one of them.” Undyne looks at me, a worried look in her eyes. “Y-you n-need to see Q-Queen T-Toriel now!” Undyne rushes to the other end of the lab and pulls out a remote. “St-Stand near the c-computer n-now! I-I can t-teleport y-you to t-the queen i-if you’re close to it.” I go up to Zak and stare into his eyes, he stares back and smiles. I hug him and look at Undyne. Undyne smiles, “good luck g-guys!” and presses the button on the remote, a bright flash of white blinds us for a moment as we teleport to the queen.


	15. FOURTEEN

Chara and I look around at the room Undyne teleported us to, a room overgrown with vines and yellow buttercups covering the floor. I look at the Queen, a goat creature like Asgore, and another human stood next to her, a knife in hand. “Stay back Chara!” I step in front of Chara and summon my Meteors, which fall to the ground with a loud clack. The human turns around and reveals her face, “Nice to finally meet you Zak”. She walks up to me and kisses me, I hear Chara gasp. I push the human away and spit, “Where is Carnie?” I make the chains clack together, making sure the human knows I’m hostile. “Oh, Carnie? She left a long time ago...She said to give you a greeting”. I grip the chains and feel warm blood come from my hands, “My name’s Frisk, and I’m here to make sure you don’t return to that traitor”. “He’s not a traitor! He’s my CREATOR!!” I whip my Meteors in a huge arc and hit Frisk in the head, knocking her down to 1/99 HP. “wh-what?! I-In one attack?!” I walk up to Frisk and a Meteor ties her to a pillar of chains. My eyes black with Rage. “You’re lucky I missed your temple.” I walk over to Queen Toriel, and see that she was stabbed in the back, not dead though, but unconscious. I pull out a bottle and pop the cap, pouring the red liquid into the wound, Toriel’s HP returning to max. I sigh, and turn to Frisk. I hold up the bottle, “Drink. Or the poison from the chains will kill you”. She looks at me confused, tears starting to form in her eyes. I hold the bottle up to her mouth and she drinks some of the liquid, her HP returning to max. “Wh-why did you heal me?” I look to Chara, and back to Frisk, “You look to much like Chara, and I need all the help I can get”. I pull out my phone and press a button, aiming at the wall. Frisk was free and now talking with Chara. “Let’s go home…”


End file.
